Load control for cutting apparatus



1964 J. J. KUIPERS ETAL 3,162,249

LOAD CONTROL FOR CUTTING APPARATUS Filed July 3, 1962 2 Sheets-Sheet 1 BY t TTORNEYS Dec. 22, 1964 J. J. KUIPERS ETAL 3,162,249

LOAD CONTROL FOR CUTTING APPARATUS Filed July 3, 1962 2 Sheets-Sheet 2 frg- Z A TTORNE YS' United States Patent 3,162,249 LOAD CGNTRGL FGR UTTH-IG APPARATUS John J. Kuipers, Chicago, and Coleman Gyure, Riverdale, L, assignors to Goodman Manufacturing (Zompany, Chicago, Ill a corporation oi Illinois Filed July 3, 1962, Ser. No. 207,288 6 Clmms. (Cl. 173--7) This invention relates to improvements in load controls for cutting apparatus and more particularly relates to an improved form of load control stopping the advance or feed of the cutting apparatus upon predetermined overload conditions.

A principal object of the present invention is to provide a control for cutting apparatus, having an overload relay controlling the stopping of the cutting apparatus, so arranged that the influence of the coil on the :armature for the relay is reduced upon operation of the relay, to accommodate the relay to drop out at a substantially higher amperage than the amperage required to drive the cutting apparatus at no load, and to thereby enable the relay to readily reset itself where the range between continuous operation and no load operation is relatively narrow.

A further object of the invention is to provide a load control for cutting apparatus allowing the cutting apparatus drive motor to operate at peak motor capacity during the entire cutting operation, and including a relay connected in series with the drive motor for the cutting apparatus, together with a control for the relay assuring the armature of the relay will always lift at the same amperage.

A further object of the invention is to provide an improved form of overload protection for a cutting apparatus so arranged as to accommodate operation of the cutting apparatus at maximum drive'rnotor load during the entire cutting operation, in which the feed continues upon encountering small overloads of short duration,

the load 'on the motor and by so arranging the relay that its armature will be extended at-a preselected overload current rating and will drop out at a higher current rating than the no load current rating, and by delayingthe time of opening of the relay witch when overload conditions" are relieved, to assure that the amperage lifting the relay armature to pick up the relay will always be uniform.

, These and other objects of the invention will appear from time to time as the following specification proceeds and with reference to the acompanying' drawings wherein: FIGURE 1 is a diagrammatic view diagrammatically illustrating a control circuit for carrying out the principles of the present invention; and

FIGURE 2 is a time load graph howing the time required to stopthe feed of the cutting apparatus at various.- overload conditions on the cutting apparatus.

'lgIn the embodiment of the invention illustrated in the drawing, I have shown'for illustrativepur'poses a cutter ;bar"11= of a' bottom cutting or universalcutting rna-. chine. The cutter bar 11 is swingablebylpower' about a vertical pivot 12 to advance the cutter bar and a cutter chain 13 orbitally driven thereabout across a working face of acoal seain'to cut a ke'rt therein, in a conventional manner.

I It should be understood, however, that the control of 3,1622% Patented Dec. 22, 1964 the invention need not necessarily be applied to control feeding movement of a cutter bar, but maybe applied to any form of cutting apparatus having a driven cutting surface and a separate power advance or feed for the cutting apparatus, such as the advancing means of a boring head of a continuous mining machine, a drill or saw or any other similar cutting apparatus.

A cutter chain sprocket 14 driven from a motor 15 through a geared reduction train 16 is provided to drive the cutter chain 13 about the cutter bar 11. The motor 15 may be a heavy duty electric motor either alternating or direct current and is herein diagrammatically shown as being an alternating current motor, energized through conductors 17, 18 and 73 under the control of a suitable controller (not shown) and no part of the present invention so not herein shown or described.

Double acting hydraulic jack 19 and 20 are pivotally connected to opposite sides of the cutter bar 11 to feed or advance said cutter bar about the axis of the pivot 12 and thereby advance the cutter chain across a mine face to cut a kerf therein. As herein shown, a pressure line 21 leading from a stop or shut-oil valve 23 is connected with the head end of the jack 20 and piston rod end of the jack 19 through pressure lines 24 and 25 respectively, leading from the pressure line 21, to eflect pivotal movement of the cutter bar 11 about the pivotal axis 12 in a feeding direction.

A pressure line 26 leading from a control valve 27 is connected with the piston rod end of the hydraulic jack 2% and the head end of the hydraulic jack 19 through pressure lines 28 and 29 respectively to eflect return movement of the cutter bar 11 to an initial cutting position after termination of a cutting operation.

The control valve 27 may be a conventional form of metering control valve selectively operable to supply fluid under pressure to the pressure line 26 or a pressure line 3% connected with the stop or shut ofl? valve 23 to supply fluid under pressure to the pressure line 21 under the control of said stop valve by manual operation of an operating handle 31. The control valve 27 may also be operable to vary the volume of fluid under pressure supplied to either of the pressure lines 26 or 39 by operation of the operating handle 31 thereof.

The source of supply of fluid under pressure for advancing the cutter bar 11 includes a tank 33 connected with a pump 35 through a pressure line 36 and connect ed with the control valve 27 through a pressure line 37. Fluid is returned from the jacks 19 and Ztlthrough the control valve 27" to the tank 33 through a return line 39. p Y

A relief valve 49 is connected from the pressure line 37 to the tank 33 to return fluid to the tank 33 upon overload conditions and when the control valve, 27 is in its ofl position and the pump 35 is operating.

The valve 23' is shown in the drawings as being a solenoid operated spool valve of a well known form including a valve spool 41 biased by a spring 43, to accommodate fluid under pressure to pass from the control valve 27 through the pressure line 30 to and through a valve chamber &4- of the stop valve 23 to the pressure line 21, to supply fluid under pressure to the hydraulic jacks 19 and 2t) to advance the cutter barl l. in a cutting direction. The valve spool 41 has an armature 45 extending from its end opposite the spring 43 througha solenoid coil 46. I Upon energization of the coil 46 the armature 45' is moved along the coil to'move the valve spool into position toblock the passage of fluid through the pressure line 21' and to by pass fluid under pressure from the pressure line 30 through a return line 47 connected to tank. The advance of the cutter bar 11 will thus be stopped upon energization of the solenoid coil conductor 73'. The shunt coil '85 is,therefore enen gized upon closing of the switch 69', through the contacts.

'thereby'close the switch; 69 ina delayed time -interval.,

'load dropsito rated motor load.

,, magnetic upward pull on the armature 53 Thelresist-i ance to. upward movement offered by the distance'the; I armature 53 projects into the coi 50, theweight ofythe An overload relay 49 having a series coil 50, connected in series with the energizing circuit to the motor 15, is provided to sense the load exerted by the cutter bar 11 on the material being out; such as a seam/of coal, to energize the solenoid coil 46.-a 'nd actuate the shut 5 off or stop valve 23,. :followingt-he sensing of an injurious overload condition on the motor 15. Theseries coil 50 isconnected in the' conductor 18 and is continually energized at the load-of the motor 15.

e The series coil 56 encircles an armature 53 having a stem 55 extending therefrom and havinga button 56 on its outerzor upper end, engageable with an aligned button 57 on the lower end of a plunger 59, depending from a casing 60 of a timing head 61 timing the 'open ing of a switch 69, deenergizing the solenoid coil 46.

The timing head 60 may be a commercial form of timing head, such as, the Westinghouse type A M Timer. The timer consists generally .in an air bellows (not shown)- delaying movement of the plunger 59 to the extended position shown in FIGURE ,1 as the armature 53 drops out. A dial knob 62 is provided to select the time at which the plunger 59 moves to its extended position.

The plunger 59 is connected with a switch arm 63 of the switch 69. The switch 69 may be a snap action switch and is illustratively shown as including the switch arm: 63 pivoted intermediate its endsv on afulcrum point 65 and a spring ;68 diagrammatically shown in FIGURE 1 as encircling the switch arm 63 between the plunger 59 and fulcrum point 65, to snap the switch into its open and closed positions in a conventional manner. The free end of the switch arm 63 .is pivotally connected with an arm 66 extending from a contact bar 67 of, the switch 69. The contact bar 67 is moved by the switch arm 63 to. engage; stationary contacts 70, to complete a :cir; cuit from a conductor 73*? to; aconductor 73 through thesolenoid coil 46 to the conductor18 through a con-v ductor 72. Thiswill energize solenoid coil 46.- and. move the armature 45 through said coil. This will move the valve spool 41. against the spring 43 in position to shut off the flow of fluid under pressure to the pressure line 21 and to the head and piston rod ends'of the respective hydraulic jacks 20 and 19, to thereby stopfeeding movement of the cutter bar 1=1. A shunt; coil 85 encir cling the armature. .53 is connectedv to the. conductor 71 A' conductor 71 having a resistor 90-connected therein leads from the shunt coil 85 and is connected with the v conductor 73. V I v, ,1 V 1 The armature 53 has a rod 74 threaded inits lower end, and depending therefrom within a cylinder 75 ofadashpot:76. ,The rod 74 has a pistonj7'7 on its lower end having a series of bleeder passageways 79 lcadingaxial- 70, contact bar 67 and conductor 73? connected to'th e' 1y therethrough. I y i I Oilisfilled in; the ,cylinder75' to a .-leyel indicated. by i 53. to adjust-the positiori ofjthej armature 153 with: respect reference character and bleeds fromg onesijde 0f the piston'77lto the other; 'upon movement of the armature. 53 along the coil 50', asthe current in saidf'coil. builds up} to certain predetermined overload current conditions. The. dashpot 76 thus formsa time delaymean s, delaying operation of the armature 53 for a time period thati varies inverely with the overload on the motor 15,; 0'

after overload" of the motor 15.? Asprin-g 81, is provided to facilitate the return of the piston 77,7-as theimotor.

During operation of the machine, .th e motor current;

passing through the series, coil 5Q will'exerta 'continuing b armature .53, stem. 55, red: 74 a =pist,on 77;, and thef 77 of the dashpot, in the 53 starts to lift, will, create a time delay in upward movement of the armature53. This will accommodate the motor. 15 to continue to operate for short intervals of time under overload'conditions. As, however, the overload conditions continue, thepiston 77 will continue its upward'movement along the cylinder 75 at a rate determined by the rate of transfer of oil from the top to the bottom of said piston and the upward force produced by overload in the coil'50, and will close the circuit between the contacts 70 and the contact bar 67, and thereby'close the circuit to the :electrornagnet 46, and elfcct the energization of 'said electromagnet. This will move the valve spool 41 in position to block the passage of fluid under pressure through the pressure line 21 and into position to return fluid from the pressure line 30 back to tank through the return line 47.

It, should here be understood that the piston 77 can only rise as fast as fluid transfers from its top to its bottom and that the length of the time delay, interval be-, fore the contact bar 67 engages the contacts 70, to close the, switch 69, varies inversely with the magnitude ofthe overcurrent. Thus, astheovercurrent increases, the time delay interval will decrease. I

The shunt coil '85 is Wound 'reversely tothe winding of the series coi-l50 and is energized upon the closing of i the switch 69 as. the armature 53 picks up. The shunt .fore, oppo,ses the series coil 50 and reduces the influence of the-current in said series coil holding the armature 53 in its extended or pick up condition, and thereby raises the current point at which the armature 53 may drop out a substantial amount above the normal current load -motor 1'5 and makes it unnecessary to shut off the motor 15 to reset the relay.

- A resistor 90 is connected in the conductor 71 to regulate the influence of the shunt coil 185011 the series coil 50, yby' regulating the opposing flux of the shunt coil and thereby regulating the; influence of. the coils 50 and 85,011 thearmat-ure 53;. Different value resistances may be connected in the line 71 in series with the shunt coil 85, to vary the opposing flux as desired andato allow the setting of the dropout point to-a requiredcurrent value and to thereby permit the relay contact closing and drop out points to be independently adjusted. V

The plunger 74 is threaded in the end'of the armature being nnderstood that the amperage required-- toglift the.

armature; varies in accordance with the vertical positipn of the'arrna'ture'with respectltothefseries. coil*5 0.,,, l1 he stem; 55'is; threaded in the opposite-end of the armature 53 from. i the} plunger 74, 1o enable the spacing between the buttons 56;a1'1d157 "to be. adjusted in accordance with V s m n o ih s 4 an a y h p c n between said buttonstwhere required. j

, The graph in IEIGUREZis; a-tim 1' ad curve illustrattlievarious load conditions on theimotor ls and (the time required to shut offthesupplyqof: fluid 'under pres- 7 sure to, the feed jacks 19 and; 2 0 for various cutter chain and, motor overload conditions, LirieLf-fA. indicates the continuous rating of the motor 15. LinefB indicates the }load. conditien ,on. the motor. required. to: drive the cutting apparatus at no load. Line C indicates an overload of 15%, at which time the motor will still run continuously at the selected setting of the armature 53 with respect to the bottom of the cylinder '75 shown in FIGURE 1. As, however, the motor load increases to an overload of over 16%, the motor current sensed by the series coil 50 will cause the armature 53 and the piston 77 to rise as fast as the dashpot fluid transfers from the top to the bottom of the piston, through the bleeder passageways 79, providing a time delay interval in closing of the switch 69, which varies inversely with the magnitude of the overcurrent. The time delay period as indicated in FIGURE 2 is one minute.

It may be seen from this figure that as the overload and overcurrent increases, the time delay interval will decrease and that when the overcurrent condition is a 50% overload condition, the armature 53 will rise instantaneously and close the switch 69 with no time delay interval.

Upon closing of the switch 69, the shunt coil 85 is energized to oppose the holding force of the series coil 50. As previously mentioned, this will raise the current point at which the armature drops out to reopen the relay contacts, above the no load motor current value, as indicated by line D, and will thereby make it possible for the armature to reset itself at a current point far higher than would be possible without the shunt coil 85.

Therefore, as the motor current drops to a current value approximated by line D, the armature 53 will drop out and the button 56 will move away from the button 5 7. The timing head 61 will, however, hold the switch 69 closed for a time delay interval sufiicient to permit the armaure 53 and the piston 77 to drop to the bottom irnit of the cylinder 75. The switch 69 will then open and the relay will be reset to again operate at the required overload conditions to energize the solenoid coil 46 and disconnect the hydraulic jacks 19 and 2th from their source of fluid under pressure.

It may here be seen that the shunt coil 85 makes it unnecessary to stop the motor 15 to reset the relay after an overload condition sufficient to pick up the armature 53 to close the switch 69, and thereby enables the motor 15 to operate continuously upon a relief in the overload thereon by operation of the valve 23.

It may also be seen that the shunt coil 85, resistor 90 and relay switch 69 make it possible to adjust the drop out point of the relay independently of the pick up point and vice versa.

While we have herein shown and described one form in which our invention may be embodied, it may readily be understood that various variations and modifications in the invention may be attained without departing from thespirit and scope of the novel concepts thereof, as defined by the claims appended hereto.

We cl-aim as our invention:

1. In an automatic control for cutting apparatus and the like,

a motor,

a cutting member,

7 means driven by said motor for driving said cuttmg member,

feeding means for advancing said cutting member to effect a cutting operation,

' electrically energizable stop means stopping operation 7 of said feeding means and the advance of said cutting member upon overload of said motor,

an energizing circuit for said electrically energizable stopmeans including an overload relay having a switch in said energizing circuit,

a series coil connected in series with said motor,

an armature movable along said series coil and operable to close said switch upon a predetermined load on said motor and coil,

a shunt coil encircling said armature and wound reversely of said series coil and energized through the 6 energizing circuit to said electrically energizable stop means upon the closing of said switch,

said shunt coil opposing said series coil upon the closing of said switch and the energization of said electrically energizable stop means and raising the current value at which said armature will move to its inoperative position,

above the no load current value of said motor and thereby enabling said switch to open and effect the continued operation of said feeding means at a higher current value than the current value for effecting opening of said switch by the series coil alone.

2. An automatic control for cutting apparatus in accordance with claim 1 in which a resistor is placed in series with said shunt coil, to regulate the current passing through said shunt coil and the current value at which the armature will move to an inoperative position to accommodate opening of said switch and the continued operation of the feeding means.

3. In an automatic control for cutting apparatus and the like,

a motor,

a cutting member,

means driven by said motor for driving said cutting member,

feeding means for advancing said cutting member to eifect the cutting operation,

electrically energizable stop means operable to stop the operation of said feeding means andthe advance of said cutting member including a solenoid,

an energizing circuit to said solenoid,

an overload relay having a switch in said energizing circuit closing upon predetermined overload conditions,

a series coil connected in series with said motor,

an armature movable along said series coil to close said switch upon a predetermined current load on said motor, a dashpot connected with said armature and delaying operation of said armature to close said switch for a time delay interval inversely proportional to the overload on said cutting member,

and a timer controlling the opening of said switch upon a predetermined reduction in the overload current including a plunger operatively connected with said switch and an engaging connection between said armature and said plunger for actuating said plunger to close said switch upon movement of said armature along said series coil upon a predetermined current load,

means moving said armature away from said plunger upon a predetermined reduction in the current load,

and thereby accommodating opening of said switch by said timer in a time delay interval determined by the setting of said timer and sufiicient to accommodate said armature to move to an extreme inoperative position prior to opening of said switch.

4. An automatic control for cutting apparatus and the l ke in accordance with claim 3 in which a shunt coil also encircles the armature and in which the shunt coil is 5. In an overload cutout for cutting apparatus having a cutting member,

an electric motor for driving said cutting member,

to effect a cutting operation, a source of fluid under pressure,

under pressure to said hydraulic motor,

a hydraulic motor for advancing said cutting member a cutting member,

a valve in said pressure line shutting off the supply of fluid under pressure to said motor, r 1 ia solenoid energizable to move said valve into position to stop the flow of fluid under pressure to said hydraulic motor and thereby to stop the advance. of said cutting member to effect the cutting operation,

an energizing circuit to said solenoid having a normally open switch therein, 1 r r a series coil connected in series with said motor,

an armature encircled by said series coil and movable along said series coil into a position to close said switch upon the building of current'in said series coil by predetermined overloads onsaid motor,

and movable into an inoperative position to accommodate the opening of said switch upon apredetermined reduction in load on saidimotor,

means accommodating the movement of said armature to an inoperative position'to effect the opening of said switch at current values substantially greater.

than the current value required to drive said motor and cutting member atno load, comprising a shunt coil wound reversely of said series coil and encircling. said armature and connected in the energizing circuit to said solenoid through said switch upon the closing of said switch,

and means delaying the opening of said switch until said armature hasmoved to the full extent. of its travel in a direction away from said switch comprising a timer having a plunger operatively connected with said switch to delay the opening of said switch and engaged by said armature to effect the closing of said switch upon the building up of'a' predetermined current value in said series coil. g

6. In an overload cutout tor/cutting apparatus having an electric motor for driving said cutting member,

a hydraulic motor for advancing said cuttingmember to effect a cutting operation,

a source of fluid underipressure, a

a pressure line connected from said source of fluid under pressure to said hydraulic motor,

a valve in said pressure line shutting off the supply of fluid under vpressure to 'said r'notor, V

a solenoid energizable to move' said valve into position to stop the flow 'of fluid under pressure to said hydraulic motor, v

an energizing circuit to said solenoid including ,a normally open switch,

V a series coil connected in said series with said motor,

an armature encircled by and movable along said series coil upon the building up of the current value of said coil to a predetermined current value caused by overload conditions on said' motor,

into a position to close said switch and movable to an inoperative position to accommodate opening of said switch upon thereduction of the current value in said series coil,

a dashpot connected with said armature and delaying operation of said armature to close said switch upon overload of said motor for a time delay interval varying inversely with the'overload',

means accommodating the movement of said armature to an inoperative position and thereby accommodating the closing of said switch at current values sub* stantially greater than the current values required to' drive said cutting memberat no load,

comprising a shunt coil encircling said armature and wound reversely of said series coil andconnectedin the energizing circuit to said solenoid through said switch and energized upon the closing of said switch,

and means delaying the opening of said switch until said armature has moved to the full extent of travel to its inoperative position comprising a timer having a plunger 'operatively connected with said switch and controlling opening of said switch upon movement of said armature to its inoperative position and -engaged by said armature upon movement of said armature along said series coil upon the building up-ot predetermined current loads in said series coil.

References Cited in the file of :this patent UNITED STATES PATENTS Newton r Oct. 22, 1963 UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No, 3, 162,, 24.9 December 22 1964 John Jo Kuipers et a1,

It is hereby certified that error appears in the above numbered patent requiring correction and that the said Letters Patent should read as corrected below.

Column 3, line 45 after "conductor" insert 18 through a COlEfi-'"" e m r Signed and sealed this 4th day of May 1965.

(SEAL) Attest:

ERNEST W. SWIDER Altesting Officer EDWARD I. BRENNER Commissioner of Patents 

1. IN AN AUTOMATIC CONTROL FOR CUTTING APPARATUS AND THE LIKE, A MOTOR, A CUTTING MEMBER, MEANS DRIVEN BY SAID MOTOR FOR DRIVING SAID CUTTING MEMBER, FEEDING MEANS FOR ADVANCING SAID CUTTING MEMBER TO EFFECT A CUTTING OPERATION, ELECTRICALLY ENERGIZABLE STOP MEANS STOPPING OPERATION OF SAID FEEDING MEANS AND THE ADVANCE OF SAID CUTTING MEMBER UPON OVERLOAD OF SAID MOTOR, AN ENERGIZING CIRCUIT FOR SAID ELECTRICALLY ENERGIZABLE STOP MEANS INCLUDING AN OVERLOAD RELAY HAVING A SWITCH IN SAID ENERGIZING CIRCUIT, A SERIES COIL CONNECTED IN SERIES WITH SAID MOTOR, AN ARMATURE MOVABLE ALONG SAID SERIES COIL AND OPERABLE TO CLOSE SAID SWITCH UPON A PREDETERMINED LOAD ON SAID MOTOR AND COIL, A SHUNT COIL ENCIRCLING SAID ARMATURE AND WOUND REVERSELY OF SAID SERIES COIL AND ENERGIZED THROUGH THE ENERGIZING CIRCUIT TO SAID ELECTRICALLY ENERGIZABLE STOP MEANS UPON THE CLOSING OF SAID SWITCH, SAID SHUNT COIL OPPOSING SAID SERIES COIL UPON THE CLOSING OF SAID SWITCH AND THE ENERGIZATION OF SAID ELECTRICALLY ENERGIZABLE STOP MEANS AND RAISING THE CURRENT VALUE AT WHICH SAID ARMATURE WILL MOVE TO ITS INOPERATIVE POSITION, ABOVE THE NO LOAD CURRENT VALUE OF SAID MOTOR AND THEREBY ENABLING SAID SWITCH TO OPEN AND EFFECT THE CONTINUED OPERATION OF SAID FEEDING MEANS AT A HIGHER CURRENT VALUE THAN THE CURRENT VALUE FOR EFFECTING OPENING OF SAID SWITCH BY THE SERIES COIL ALONE. 